Noctilucent CloudsThe northern season for NLCs is finished. According to NASA's AIM spacecraft, the last clouds were observed over Greenland on Aug. 27th. Now the waiting begins for the southern season expected to begin in November.

Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2015 Oct 01 2200 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

30 %

35 %

MINOR

15 %

20 %

SEVERE

01 %

05 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

15 %

MINOR

25 %

25 %

SEVERE

40 %

50 %

Thursday, Oct. 1, 2015

What's up in space

Marianne's Heaven On Earth Aurora Chaser Tours Chasethelighttours.co.uk invites you to join them in their quest to find and photograph the Aurora Borealis. Experience the winter wonderland in the Tromsø Area.

DARK PLASMA ERUPTION, EARTH-DIRECTED? Yesterday, Sept. 30th, a massive plume of dark plasma rose up from the sun's western limb and erupted. NASA's Solar Dynamics Observatory recorded the blast:

False colors in the movie correspond to different wavelengths of extreme ultraviolet (EUV) radiation. Greens and yellows denote hot gas. The erupting plasma looks dark red because it was cooler and denser than its surroundings.

Fragments of the plume flew away from the sun, forming the core of a bright coronal mass ejection (CME): movie. There is a chance the CME will deliver a glancing blow to Earth's magnetic field on Oct. 3rd. If so, the impact will probably cause G1-class geomagnetic storms. Aurora alerts: text or voice

DAYTIME METEOR SHOWER: You can't see them, but they're there. Overwhelmed by the glare of the sun, as many as 20 meteors per hour are shooting through the daytime sky on Oct. 1st. Prof. Peter Brown sends this report from the University of Western Ontario: "The Canadian Meteor Orbit Radar(CMOR) has been detecting strong daytime meteor activity over the last two days, resulting from Daytime Sextantid shower." The shower's radiant is labeled 'DSX' in this CMOR radar map made just hours ago:

"This daytime shower is linked to asteroid 2005 UD," says Brown. "It is also related to the Geminid meteor shower, which itself comes from asteroid 3200 Phaethon. Thus, the Daytime Sextantids are part of a broader complex of interlinked showers, probably the remnants of some long-ago disruption of a larger parent body."

The Daytime Sextantids usually last for about two weeks, so the shower will be detectable for another week, but today/tomorrow is the peak. Tune into Space Weather Radio for live radar echoes.

"While the Daytime Sextantid shower won't put on much of a show in nighttime skies, another meteor shower is coming which will," adds Brown."CMOR is now detecting the first hints of the Taurids. According to some predictions, the Taurid shower will be unusually strong this year, potentially showing many fireballs in late October – early November. Stay tuned!"

COSMIC RAYS DURING THE LUNAR ECLIPSE: On the evening of Sept. 27th, Spaceweather.com and the students of Earth to Sky Calculus conducted a routine flight of their cosmic ray payload to the stratosphere. Routine, that is, except for one thing: the balloon flew at night during a lunar eclipse. One of the goals of the flight was to compare radiation levels at night to those recorded during the day. Here are the data they recorded:

Compare this plot of radiation vs. altitude to a similar plot recorded in broad daylight only a few days earlier. They are almost identical. Radiation levels in the stratosphere matched at the 1% level. Radiation levels at aviation altitudes (where planes fly) agreed within about 3%. Night and day were the same.

This simple experiment highlights something that is already well known to researchers. Cosmic rays in Earth's atmosphere come mainly from deep space. They are accelerated toward Earth by supernovas, colliding neutron stars, and other violent events in the Milky Way. Flying at night is no safeguard against these energetic particles because they are everpresent, coming at us from all directions, day and night.

HEY THANKS (and Happy Birthday): The lunar eclipse flight was sponsored by Spaceweather.com reader JR Biggs, whose donation of $500 paid for the supplies neccesary to get the balloon off the ground. To say "thank you" for his contribution, we flew a birthday card for his daughter to the edge of space:

Happy Birthday to Autumn! She will be watching a complete video of the flight when she turns 4 on Oct. 10th.

Readers, if you would like to support a research flight and send your birthday card, business logo, or other photo along for the ride, it only costs $500. Contact Dr. Tony Phillips to make arrangements.

These measurements are based on space weather balloon flights, described below.

Introduction: Once a week, and sometimes more often, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere. These balloons are equipped with radiation sensors that detect cosmic rays, a form of space weather important to people on Earth. Cosmic rays can alter the chemistry of the upper atmosphere, seed clouds, spark exotic forms of lightning, and penetrate commercial airplanes. This last point is of special interest to the traveling public. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. From now on we will present the results of our regular weekly balloon flights in this section of our web site. Here is the radiation profile from our latest flight:

Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are nearly 100x sea level.

Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Sept. 27th measurements, a plane flying at 45,000 feet is exposed to 288 uRads/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in 5 hours.

Stay tuned for improvements to this section in the days and weeks ahead as we develop a glossary and better plain language strategies for communicating this information. Suggestions are welcomed.

All Sky Fireball Network

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

On Oct. 1, 2015, the network reported 18 fireballs.(18 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.